Surface active compositions



Patented Oct. 31, 1950 2,528,136 at Y? I sURF oE YAoTWiioo rosI'r ons Herman B. G'oldstein, Cranstdmand Armand S. Wal'dman, Providence, R. I., as'signors to Sun Chemical Corporation, New York, N. Y., a corporation of Delaware N Drawing.

' This invention relates to surface active com positions, and more particularly, to surface ac tive compositions useful in the processing an finishing of textile materials, y

Compounds displaying a high degree of surface 1 activity have attained a considerable degree of importance in the processing and'finishing of textile materials. Especially is this'ztrue of a class of such'compounds known as non-ionic surface active agents, particularly thosecompounds belongingto this group-which are water-soluble. Such compounds arecharacterized by a high degree of wetting and penetrating action, particularly for aqueous solutions containing. electrolytes and metallic salts; In this respect, the non ionic surface active-agents display a far greater stability toward hard 'water,---alkali earth} or heavy metal salt solutions than do" cationic or anionic-surface active agents of a comparable degree of water solubility, and enables these compounds to perform theirfunctions of wetting, cleansing, penetrating or emulsifying undera wide variety of operating conditions} Further more, the non-ionic surface active agents are ustact with mild acid or alkalis and may be utilized under such conditions without appreciably altering their effectiveness.

Typical of such non-ionic surface active agents K are the waterjsoluble higher fatty acid esters of the pplyethylene glycols (moluweight approxi mately 400-750), and particularly the partial or mono-esters of predominan'tlysaturated higher fatty acid materials with such polyethylene glycols. These particular compoundsexhibit very good wetting properties, are effective detergents and emulsifiers, and as such have found wide use in scouring, desizing, dyeing and washing operations. Since these surface active agents are generally stable and effective in hard water and in"-' aqueous solutions containing metallic salts, they have been found to be effective emulsifiers when used with soaps, preventing the formation of insoluble lime soaps which are ordinarily formed 7 by soap in hard water and which have a tendency to cause specks upon the fabric being treate ed. Moreover, such lime soapsare ordinarily'difficult to remove 'in thelrinsingoperation and when deposited upon the. fabric act asa waterdyeing, The polyethylene glycol fatty acid mono"- ually little or not at all affected by limited coni proofing agent which preventtuniform a'nd even Applicationfqctolier Serial No. 52,600

, 5Claims. (Greta-435s), f I

esters are also good penetrants'and, as -such,-:act

as effective dye assistants and leveling agents in the dyeing of "various'types oi -textile materials.

However, vthe surface; active properties ofifthe I polyethylene'glycolfatty acid esters and the effectivene'ss of these compounds for such purposes as are mentioned above are governed in large measure by the degree of esterification of the reaction pr'oductf Since theipolyethylene glycols possess two hydroxyl groups available for esterificatio'n,fupon such reaction with. an ester forming material-,fthere may be formed either the mono esterp the di-ester, or a mixture of the mono-ester and-the -:di-=esterof the particular polyethylene glycol so treated, depending upon the proportionsof zthe reacting materials to each other'and theconditions .of reaction; While it is evidentthat the properties and characteristics of: these esters willbe widely dissimilar from each other'andi among themselves when various kinds of ester forming materials are employed, it will also-:befdund that the-inono-ester and the die'ster of' a -polyeth'ylene glycol will ,showwidely divergent characteristics as regards their surface active properties, water solubility, etc., even-when the ester forming material employed in preparingthese'products isthe same in each case. For example, the'saturated higher fatty acid monoesters of polyethyleneiglycols having a molecular weight :of approximately 400 and higher are comiplet'ely soluble in water, decreasins soluble in oil, and possess surface active characteristics peculiar to th'e" non-'ionicsurface active agents mentioned above The saturated higher fatty acid di-festers' of polyethylene glycols having a molecular weight of 1000 and lower are water insoluble; oil soluble, and 'possessrelatively few of the surface active properties usefulin such tex t-ile' application's'as are set forth above, especially for such applications where complete water solubility is a necessity." Therefore, the presence of anyvsubstanti'al 'a'mount ofthe di-e st'er in admixture with the mono-ester would have a tendency to appreciably decrease the surface activity characteristic of the saturated higher fatty acid --mono-"esters of the polyethylene glycols and athereby seriously limit the usefulness of these compounds.

A In,.preparing these :esters in the conventional amanner; by direct ester'i'fication of thefa'tty acid "a nd--..-theli glycol=,::the degree of esterification is lnorinallycontrolled by the amount of the react- ;ants' employed, that is, in Imolecular relation to S11Z61f11d' eSSeiitia11y be formed'in prefersnee to the nd'er conditions favorable l 3 (ii-ester. Similarly, if two moles of the fatty acid are reacted with one mole of polyethylene glycol and a substantially complete reaction is obtained, only the di-ester is formed. However, it has been found that in preparing the monoester of the polyethylene glycols, substantial amounts of the di-ester are formed, even when. the molecular proportions of fatty acid to glycol are such as to favor the theoretical formation ofonly the mono-ester.

tions involving separation of the di-ester and the unreacted constituents must be employed, rendering the process moreinvolved and more costly than is desirable.

There has recently been developed forcom mercial use a series of mono-methylatedpoly k,

ethylene glycols, ranging in average molecular weight from approximately 350 to 750s-Thesecially those containing from about 12 to ,16-car-.

bon atoms, form non-ionic surface active agents not only similar in their'properties and-characteristics to the analogous polyethylene glycol mono-esters, but also of greatlyenhanced surface activity and wettingu-powerj .Since; the

methoxy polyethylene glycols have .onlygone hydroxyl group available for esterification, the possibility of di-ester formation such as normally occurs in the esterification of the polyethylene glycols is eliminated and essentiallypureifatty acid mono-esters maybe prepared. ,Therefore, such esters prepared by the direct esterification of the saturated higher fatty acids and the methoxy polyethylene glycols, represent a distinct improvement over the polyethylene glycol fatty acid esters in that they maybe more easilyprepared, that essentially the pureester can be obtained, and in that such esters possess a;higherdegree of surfaceactivityand wetting-power than do the corresponding polyethylenezglycol fatty acid esters.

However, in preparing these esters, we have discovered that the surface activity of such'products'prepared by the esterificationofnthe methoxy polyethylene glycols and l the saturated higher fatty acids may be further improved -by limiting the extent of the reaction so that the resultant reaction product possesses an acid value within the range of approximately 26-143.

We have further found that, optimum wetting power of such products is obtained only within the range of'an acid value'of 26-43..

By the term acid value as utilizedin-th'e present invention is meant the number ofjmilligrams of potassium hydroxide requiredto neutralize a one gramrsample of the-material so tested. By the term wetting power. or"-wetting-'effi- 'ciency, as utilized in ithe present. inVention;-.is meant the speed of wetting ras' determined-by means of the Draves test, which? 515 theroflic-ial method for the; evaluation; of wetting :ag'ents adopted by the AmericanAssociationgof' Textile ett psasent that is requir tecause Therefore, in order to obtain the pure mono-ester, a series of op'era- 4 the sinking of a 5 gram skein of unboiled, grey, 2 ply cotton yarn in a standard period of time when the skein, carrying a hook of standard weight, is held beneath the surface of the wetting 5 solution by a heavier weight. The value of the concentrationto cause sinking in the standard time is obtained by interpolation from a curve plotted from average values of sinking times gidetermined with known concentration of wetting Inversely, this method also consists of determining the time required for 5 gram skeins of .un boiled, grey 2 ply cotton yarn when weighted with a'sinker of standard weight to sink when submerged in a solution of standard concentra- ;tion of wetting agent. The time of sinking is an I; indication of the wetting qualities of the particular wetting agent utilized. This is the method utilized in the present invention to determine the comparative wetting power of the various compositions 50 tested. Itwill be noted that this test indicates the wetting quality of a solution of, the wetting agent upon a textile surface and does not measure thesurface tension directly.

In-carrying out our invention, equimolecular amounts of a methoxy polyethylene glycol and a fatty acid material composed essentially of saturatedhigher fatty acids are charged to a suitable reaction apparatus, together with a small amount of a catalytic agent. The charge is then heated to a predetermined temperature, sufiicient to promote reaction between the glycol and fatty acid material, the water of reaction being continuously removed as formed. At various time intervals, a small portion of the reacting materials is withdrawn from the. reaction vessel and tested both for acid value and wetting power. In this manner, the wetting power of the reaction product is determined at various stages of esterification, and the trend of increased or decreased wetting power in relation to the acid value, which is an; indication of the extent of the esterification reaction, may be followed, and the point or acid value range within which the wetting .power is at its greatest may easily be determined.

,To demonstrate the present invention, the following illustrative examples are set forth.

Example I The above materials are charged to a threeneck flask equipped with a tube arranged so as -to'extend'beneath the surface of the charged material to provide entry for .an inert gas, such as carbon dioxide, and witha condensor to collect and remove the water of reaction. Heating is'begun and a stream of carbon dioxide is started bubbling through the admixture to provide moderate .agitation of the reacting mate- ,rials. The carbon dioxide also serves to provide an inert gaseous blanket to prevent discoloration of the reaction product from the air, and. aids injthe removal of the water of reac- ;tion. :The-reactionmixture is thenbrought to a temperature of 127: :3 C. which is mainta-ined'forzthe duration of the reaction.'-,After meachi-ng :thereaction temperature, grams samples of the reaction mixture are removed at 212- regular time .intervals and are tested for a'cid value and wetting efiiciency. It was found that the wetting efficiency of the samples so tested was at its maximum at an acid value of 33.5 and that it suddenly fell ofE-ata point below an acid value of about 26.-. w

The'following table demonstrates the tests made. 3 a

Elapsedtim Date; Sinking full" -"ga g? Acid Value Time 2 gm; Der gg ig g of sample liter ln (11513121851 testing e, water at Hours Seconds 1 40. 5 11 2 33.5 .0 3- 30.0 10.4 4 26. O ,11. 1 s 19.4 19.8

Example II V "The reaction described in .Example I, em-

ploying the samezlnaterialsinthe same amounts,

was repeated at a reaction temperature of 109:(:l C. The'results obtained upon testing 100 grams samples; withdrawn'iat' regular intervals, are asfollows.

Elapsed time Draves Sinking 4 after Feachmg Acid Value Time 1 gm. per macho of sample liter in distilled perature before water at 25 0- testing sample Seconds lit 22'? 1 i 22': 1 2 2% 2s. 2 '28. 4 22. 7 40. 2 18.5 42,1

The percentage of ester formed in the above reaction at an acid value of 43 is approximately 43% by weight of the components present in the reaction mixture. 7

From the above table it can be seen that the optimum wetting efiiciency of the reaction product at various stages of esterification lies within the range of acid value of approximately 28 to 43. At a point slightly-below acid value 28,

the wetting efficiency begins to decrease and be-.

comes worse as the reaction nears completion. Therefore, the above trend indicates that not only will the wetting efficiency of the pure ester obtained by carrying the reaction to completion be lower than the wetting power of a reaction mixture exhibiting in the instant case, an acid value within the range of approximately 28 to 43, but also that the optimum wetting efiiciency of the products secured by' such reaction lies within a certain specific range of acid value. These facts are further borne out in the following example.

Example III Parts by weight Methoxy polyethylene glycol (average mol. weight, 550) 820 Distilled coconut fatty acids (mol. weight,

224) (acid value--250) 335 Para-toluene sulfonic acid 5.97

6 The reaction was carried out. according. to the procedure outlined in Examplev I. and thecfollowing results were obtained.

Elapsed time V i Draves Sinking ig ggg fif Acid {Value Time lgonsp r. peraturebefoer of sample litermdlstilled I a i l em p .W

S n'ds 43 15.1. .31 13.6

I The percentage of ester formed at an acid value)of .43, utilizing the above reactants inthe proportions set forth, is approximately "40.0%

-by weight of the components present in the .re-

action .inixt'ur'e." V 1 Here again, optimum wetting efficiency was obtained within a specific acid value. range, with a sudden deterioration of the wetting efficiency occurring at an acidvalue slig-htlyless than approximately .27 ,and gcontinually becoming worse as the reaction approached'completion.

j Therefore, by limiting the extent of the reaction involving the'methoxy polyethylene-glycols and the saturated, higher fatty acids to. a point Within an acid value range of approximately 26 'to 43, compositions-may be obtained which not no appreciable decrease in-the effectiveness of their wetting properties under such conditions. The compositions of the present invention are also excellent dispersants and as such may be utilized to promote more level dyeing of fabrics.

While the products of the present invention and the processes of-making the same, as outlined above, constitute preferred embodiments of the present invention, changes may be made therein without departingfrom the scope of the present invention as defined in the appended claims.

What is claimed is;

1. A surface active composition comprising, in

admixture, at least 40 per cent by weight of an ester of a mono-methylated polyethylene glycol having a molecular weight within therange of approximatel 350-750 and a fatty acid material,

said fatty acid material being composed essentially of saturated higher fatt acids, a monomethylated polyethylene glycol, having a molecular weight within the range 0f approximately 350-750, and a fatty acid material composed essentially of saturated higher fatty acids, the said glycol and the said fatty acid material being present in approximately equivalent. molar proportions, said composition having an acid value within the range of 26-43.

2. A surface active composition comprising in admixture, at least 40 per cent of an ester of a u 7 mono-methylated polyethylene glycol having a molecular weight within the range of approximately 350-750 and coconut fatty acids, a monomethylated polyethylene glycol having a molecular weight within the range of approximately 350-750, and coconut fatty acids, the said glycol and the said fatty acids being present'in approximately equivalen't molar proportions, said composition having, an acid value. within the range of 26-43.

3. A surface active composition Comprising, in admixture, at least 40 per cent by weight of an ester of a mono-methylated polyethylene glycol having a molecular weight within the range of approximately 350-750 and lauric acid, a monomethylated polyethylene glycol having a molecular weight within the range of approximately 350-750, and lauric acid, the said glycol and the said fatty acid being present in approximately equivalent molar proportions, said composition having an acid value within the range of 26-43.

4. A surface active composition comprising, in admixture, at least 40 per cent by weight of an ester of a mono-methylated polyethylene glycol having a molecular weight within the range of approximately 350-750 and myristic acid, a monomethylated polyethylene glycol having a molecular weight within the range of approximately 350-750, and myristic acid, the said glycol and the said fatty acid being present in approximately.

equivalent molar proportions, said composition having an acid value within the range of 26-43. 5. A method of preparing a surface active 8 composition-comprising the process of effecting esterification of approximately equivalent molar proportions of a fatty acid material with a monomethylated polyethylene glycol having a molecular weight within the 'range of approximately 350-750, said fatty acid material being composed essentially of saturated higher fatty acids, wherein said esterification is carried to at least 40 per cent completion of esterification and wherein the esterification is haltedzwithin an acid value range;of 26-43. r

HERMAN BVGOLDSTEIN. ARMAND s. WALDMAN.

" REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,970,573 Schoeller Aug. 21, 1934: 2,269,529 Goldsmith"; Jan. 13, 1942 2,275,494 I Bennett Mar. 10, 1942 FOREIGN PATENTS Number 1 oountr'y a v a Date- 468,533 Great Britain July 7, 1937 OTHER REFERENCES Carbowax Compounds and Polyethylene Glycols, Carbide and Carbon Chemicals Corporation, 1946. 

1. A SURFACE ACTIVE COMPOSITION COMPRISING, IN ADMIXTURE, AT LEAST 40 PER CENT BY WEIGHT OF AN ESTER OF A MONO-METHYLATED POLYETHYLENE GLYCOL HAVING A MOLECULAR WEIGHT WITHIN THE RANGE OF APPROXIMATELY 350-750 AND A FATTY ACID MATERIAL, SAID FATTY ACID MATERIAL BEING COMPOSED ESSENTIALLY OF SATURATED HIGHER FATTY ACIDS, A MONOMETHYLATED POLYETHYLENE GLYCOL, HAVING A MOLECULAR WEIGHT WITHIN THE RANGE OF APPROXIMATELY 350-750, AND A FATTY ACID MATERIAL COMPOSED ESSENTIALLY OF SATURATED HIGHER FATTY ACIDS, THE SAID GLYCOL AND THE SAID FATTY ACID MATERIAL BEING PRESENT IN APPROXIMATELY EQUIVALENT MOLAR PROPORTIONS, SAID COMPOSITION HAVING AN ACID VALUE WITHIN THE RANGE OF 26-43. 